Base Station Antenna Dummy Elements Reduce Mutual Coupling

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Solution Overview

Problem

Mutual coupling between radiating elements in base station antennas, particularly in multi-band antennas, leads to reduced isolation and performance issues such as decreased azimuth beamwidth and front-to-back ratio due to close proximity of subarrays.

Innovation Solution

Incorporating dummy elements between subarrays of radiating elements that are not connected to the feed network, which absorb or reflect energy to reduce mutual coupling, thereby improving isolation and performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If radiating elements are integrated in a small area to increase capacity, then antenna capacity and data rates are improved, but mutual coupling between subarrays increases and isolation decreases

Engineering Contradiction:
Improveantenna capacityVSAvoidmutual coupling
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces dummy elements as intermediary structures positioned between radiating subarrays. These dummy elements act as mediators that interact with the electromagnetic fields of adjacent radiating elements, providing isolation and reducing mutual coupling effects while allowing the radiating elements to maintain their high-capacity configuration.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent extracts the isolation function from the radiating elements themselves by introducing separate dummy elements that are not connected to the feed network. This separation allows the radiating elements to focus on radiation while the dummy elements handle the isolation function, resolving the contradiction between compact integration and mutual coupling reduction.

Inventive Principle:
Principle #2Taking out (Extraction)

2Area of stationary object

If spatial separation between radiating elements is reduced to increase integration density, then antenna compactness is improved, but mutual coupling between subarrays becomes more severe

Engineering Contradiction:
Improveantenna footprintVSAvoidmutual coupling
Core Design Contradiction:
Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

Dummy elements serve as intermediary structures that fit in the spaces between closely spaced radiating elements. They provide electromagnetic isolation without requiring increased spatial separation, enabling compact antenna design while maintaining low mutual coupling through the mediating effect of the dummy elements.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent addresses the spatial constraint by introducing elements in additional dimensional configurations. The dummy elements are positioned and oriented to interact with fields in dimensions perpendicular to the main radiation direction, providing isolation without increasing the primary footprint of the radiating structure.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Object-affected harmful factors

If dummy elements are added between subarrays to reduce mutual coupling, then isolation and performance are improved, but device complexity increases

Engineering Contradiction:
ImproveisolationVSAvoidantenna structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The dummy elements are designed as simple, inexpensive structures that do not require active components or complex feed networks. They can be implemented as passive metallic or dielectric elements, providing effective isolation without adding significant complexity or cost to the overall antenna system.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

By extracting the isolation function into separate dummy elements that are not connected to the feed network, the patent simplifies the overall system architecture. The radiating elements remain simple connected structures while the dummy elements provide passive isolation, dividing the system into functionally independent parts that reduce overall complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The use of dummy elements significantly increases isolation between subarrays, enhancing the 3dB azimuth beamwidth and azimuth front-to-back ratio, resulting in improved antenna performance across various frequency bands.

Implementation Method 1

The dummy elements are not connected to the feed network of the antenna and serve to reduce mutual coupling between radiating elements through energy absorption or reflection

Methodology Applied
Scientific EffectElectromagnetic absorption: Absorption (EM radiation)

Implementation Method 2

The dummy elements are not connected to the feed network of the antenna and serve to reduce mutual coupling between radiating elements through energy absorption or reflection

Methodology Applied
Scientific EffectElectromagnetic reflection: Reflection

Data Source

PatentEP3257102B1Base station antenna with dummy elements between subarrays
Publication Date: 2021.08.25 COMMSCOPE TECHNOLOGIES LLC
  • EP3257102B1 patent drawingFigure 1
  • EP3257102B1 patent drawingFigure 2
  • EP3257102B1 patent drawingFigure 3

AI summary

Apparatus include two or more radiating elements connected to a feed network of an antenna, and one or more dummy elements positioned between the two or more radiating elements. The dummy elements are not connected to the feed network of the antenna. Such an arrangement may result in reduced mutual coupling of the two or more radiating elements, and increased antenna performance.